LONDON (AP)  The group that determines soccer rules has expanded the experimental use of two extra assistant referees into this season's European Champions League, a move made following a series of mistakes during the World Cup.

Use of officials behind the goals was tested in last season's Europa League, and the International Football Association Board says it will decide in 2012 whether to permanently adopt the change.

The introduction of officials alongside the traditional referee and two linesmen is designed to help determine whether balls cross the goal line.

Continued experimentation means discussion of goal-line video technology may be postponed at the next meeting in October, when the IFAB sets its March agenda.

Debate on goal-line technology intensified at the World Cup after England was denied a goal against Germany because officials failed to detect a shot by Frank Lampard crossed the line after bouncing down off the crossbar.

This week at the Women's Under-20 World Cup in Germany, a shot from France's Lea Rubio struck the crossbar, bounced over the line and spun back into play, but English referee Alexandra Ihringova waved away claims for a goal and ordered play to continue.

IFAB's technical subcommittee, which met in Cardiff, Wales, ruled national associations, confederations or competitions must cover the cost of the experiment.

It has been approved for a total nine competitions including France's League Cup, Brazil's Rio de Janeiro Championship and Asia's President's Cup club tournament.

Three other events could take place if their ruling bodies agree.

CONCACAF general secretary Chuck Blazer said Mexico applied to be involved after Argentina was credited with a goal from an offside position against the Mexicans at the World Cup.

Both Mexico's Apertura and Clausura tournaments will feature the trial.

"They said, 'It would be really great if our league could be involved.' They were very receptive," Blazer said. "It's not a light undertaking."

Copyright 2010 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

To report corrections and clarifications, contact Standards Editor Brent Jones. For publication consideration in the newspaper, send comments to letters@usatoday.com. Include name, phone number, city and state for verification. To view our corrections, go to corrections.usatoday.com.

Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. Read more.